An article resting on irregular, uneven flooring tips as weight is shifted about its surface. This can be merely annoying when the article is a piece of furniture, such as a table or the like, or even dangerous in the case of scaffolds, machinery, ladders and so forth where instability could lead to injury. Over the years, devices to stabilize articles have been proposed, most of which involve adjustable legs or shims that compensate for uneveness.
Nevertheless, instability remains a common problem.